Sockets,BufferedWriter.flush() not sending the data

Question

The following code works ,the server gets the com string and then the connection closes,if I uncomment the bw.flush() and its next line ,The server doesn't get the com string anymore and it just waits on the br.readLine() for a response(which will not get since the server didn't got the com string),if I move the bw.close() and put it in the bw.flush() position the br.readLine() will throw a Socket closed exception.

public static void setupClient(String[] args) throws UnknownHostException, IOException{
    Socket client = new Socket(InetAddress.getLocalHost().getHostName(), Server.DEFAULT_COMMAND_PORT);
    BufferedWriter  bw =new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));
    BufferedReader  br =new BufferedReader(new InputStreamReader(client.getInputStream()));
    String com=args[0]+(args.length==2?args[1]:"");
    bw.write(com);
//  bw.flush();
//  System.out.println("response:"+br.readLine());
    bw.close();
    client.close();
}

Answer 1

You are reading lines but you aren't writing lines. readLine() returns when it reads a line terminator or end of stream. That's why it works when the peer closes instead of flushing. You need to use BufferedWriter.newLine() after your write().